Introduction
Last year (2010), around August, there was a news item about a few hundreds of tonnes of explosives going missing in transit between Rajasthan and Madhya Pradesh. Although mainly intended for use in mining, the explosives (gelatin sticks) can be used in fabricating IEDs too, so the concern over the missing explosives falling into the wrong hands was real and pressing. A police investigation that followed unearthed the fact that top officials of the company manufacturing the explosives had channeled the missing material to an unofficial distribution channel. Although this news abated the concern about the explosives having fallen into the wrong hands, it raised fresh concerns about the safe-keeping and tracking of explosive materials in India.
This brief looks at the latest technological developments in Explosives Trace Detectors (ETD) and potential use-cases for ETDs in Homeland Security, given the concerns raised in the previous paragraph.
Explosives Trace Detectors (ETD)
Explosives Trace Detectors are devices that are able to detect explosives, even if they are well concealed or camouflaged, through sniffing vapours or sampling traces or a combination of both techniques.
ETDs are typically evaluated on the basis of their sensitivity, their false-positive rate, and their volume/weight package.
Sensitivity:
Sensitivity is defined in terms of either:
False-positive rate:
Some of the technologies produce higher false alarms than other, mainly on account of the technology and the material being detected; so, it does make sense to have an understanding of the explosives attempting to be detected, before deciding on a particular technology.
Volume/Weight package:
ETDs come in various shapes and sizes – handheld to portable to fixed – and the use-cases for the device need to be understood before deciding on the ETD. Some ETD technologies (chemiluminescence or IMS) are amenable to portability, while others (mass spectrometry, for example) are only available as fixed installations.
ETDs implement different technologies for the detection of explosives, and a summary of the popular technologies are provided in the table below. Sometimes Gas Chromatography (GC) is combined with some of the technologies below to deliver higher sensitivity.
| TECHNOLOGY | DETECTION PRINCIPLE | PROS AND CONS | ||||||||||
| Atmospheric-pressure chemical-ionization mass spectroscopy | Target object is ionized by an electric field under atmospheric pressure, and molecular mass of ions is determined in order to identify target object. |
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| IMS (Ion Mobility Spectrometry) or GC/IMS | Mobility of ionized molecules of target object is measured under atmospheric pressure in order to identify constituents. |
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| Chemiluminescence or GC /Chemiluminescence | Utilizing chemiluminescence of specific molecules in target object to identify explosive traces |
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| Antigen-antibody | Detector is set up so that as an antigen, a specific molecule of an explosive reacts with an antibody. Detecting this antigen/antibody reaction forms the basis of this detection method. |
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| Thermo redox | Based on decomposition of explosive substance followed by the reduction of the NO2 groups. Explosive vapors are pulled into an adsorber at a high rate and then pyrolized. The presence of NO2 groups in the pyrolized products is then detected. |
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| Amplifying Fluorescent Polymer (AFP) | Based on synthesized polymers which bind to explosive molecules and give an amplified signal upon detection. |
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Applications in Homeland Security, in India
Standard uses of ETDs involve deployment of handheld or portable equipment for critical infrastructure protection, as part of airport/seaport safety measures, as part of a VIP security detail, or in the operations of bomb-disposal squads.
The deployment of ETDs for monitoring the movement of goods across the country is usually put on a low-priority by law-enforcement agencies, on account of the need to co-ordinate with other government departments or agencies (e.g. commercial taxes, railways, etc.). However, given the quantum of goods moved over roads and rails in India, there is sound logic for implementing trace detection facilities at state commercial tax check-posts and at freight train hubs.
Mobile vans with ETDs:
The easiest implementation is equipping a vehicle with ETD equipment and trained personnel at state border commercial tax check-posts and at freight hubs of Indian railways. Scanning will be carried out manually. Although easy to implement, such a process would be time-consuming.
Mobile ETDs:
The alternative is to equip a vehicle with a ETD portal through which transport units pass, with scanning
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| Source: www.viewpointonline.net |
happening automatically, as the unit is driven through the portal. The vehicle can be deployed at check-posts or freight hubs, based on need or threat perception, and can be shared among several such locations, thereby reducing the investment in infrastructure.
Conclusion
Given the need to closely monitor and identify movement of explosives, it is about time state police started planning for deploying ETD solutions at freight focal points.
Mistral offers various types of homeland security solutions on mobile platforms. Integrating ETD equipment in the Mistral mobile command & control centres can be carried out by the Mistral Homeland Security division.
